Theory is second best to practice. The best way of improving your English is by real everyday situations.

making introductions small talk how to say no English at the restaurant

English at immigration saying good-bye in English Englisch at the bar/pub

English on the phone

You might want to compare grammar with the scaffolding when building a house. It is necessary if the learner is an absolute beginner. From a certain point in time though it is necessary to dismantle it and try to test your English in the wild.
These exercises are meant to provide you standard sentences in typical everyday situations to help you over the hump.